Please refer to the standard HTTP response codes. Where anything starting with 2XX signifies approved, 4XX means client error and 5XX indicates server error. When the response codes start with 4XX or 5XX, an error object will be returned to explain further the reason for this failure. See Appendix A for error code descriptions.
Sample response Codes obtainable are below. Note that this list is not exhaustive.
| S/N | Response Code | Response description |
| 1 | E10 | The service field tag has not been populated. Please ask Interswitch Support for more help. |
| 2 | E11 | This requests expects a transactionType field to be set and it is not. Please ask Interswitch Support for more help |
| 3 | E12 | SecurityToken header is missing. |
| 4 | E13 | Username or password is wrong. |
| 5 | E14 | Missing content type header. |
| 6 | E15 | The transaction you are trying to do is not supported |
| 7 | E16 | The service you have specified is not available |
| 8 | E17 | The service provider you have specified has not been set up on the platform. |
| 9 | E18 | The service is unreachable at the moment |
| 10 | E19 | A bad response was received from service provider |
| 11 | E20 | Your request has timed out |
| 12 | E21 | An unknown error has occurred. Please ask Interswitch Support for more help. |
| 13 | E22 | Access key has not been supplied. Ensure the Authorization header has been set appropriately. |
| 14 | E23 | Nonce has not been supplied. Ensure the Nonce header has been set appropriately. |
| 15 | E24 | Please synchronize your time with the server and ensure your time is not outside of 30mins of the Server local time. The standard time zone used is GMT |
| 16 | E25 | Nonce has already been used |
| 17 | E26 | Signature failed for this request. Please ask Interswitch Support for more help. |
| 18 | E27 | An unknown error occurred during Authentication. Please ask Interswitch Support for more help. |
| 19 | E28 | Your credentials do not have access to this resource |
| 20 | E29 | Timestamp is missing in your header |
| 21 | E30 | SecurityToken header is bad. |
| 22 | E31 | XML data is badly formatted |
| 23 | E32 | JSON data is badly formatted |
| 24 | E33 | Keystore is not accessible. Contact Interswitch. |
| 25 | E34 | The system is busy at the moment, please try again later. |
| 26 | E35 | Bad request to service provider. Contact Interswitch. |
| 26 | E36 | Bad request to service processor. Contact Interswitch. |
| 27 | E37 | Bad request from client. Kindly check your message. |
| 28 | E38 | Bad response from service provider. Contact Interswitch. |
| 29 | E39 | Bad response from service processor. Contact Interswitch. |
| 30 | E40 | Bad response to client. Contact Interswitch. |
| 31 | E41 | Bad request from client. Kindly check your message. |